Rocket motor performance is a greatly dependent on rocket nozzle throat erosion. This erosion is caused by heat and corrosive gasses, but also particularly by combustion particles being propelled against the interior walls of the nozzle. As the erosion persists, the performance of the rocket motor tends to decrease.
To combat the undesirable erosion or ablation of the interior walls of rocket nozzles due to particle impact, there has been proposed in the prior art numerous interior protective liner schemes. For example, U.S. Pat. No. 3,737,102 to Garard et al. discloses a rocket nozzle having a layer of hard anodize coating over which is placed an ablative layer to produce a layer of cool gas alongside the nozzle walls during burning.
U.S. Pat No. 3,284,874 to Grina is similarly directed to an erosion resistant liner having a segmented construction in the form of frusto-conical sleeves capable of venting gasses accumulating at an insulator-liner interface.
In both of the above-noted patents emphasis is placed on protecting, directly, the interior wall of the nozzle. However, this approach requires relatively thick coatings or layers of specialized materials thereby adding additional weight to the overall vehicle to which the nozzle is attached. This material also adds additional expense. Moreover, the added weight detrimentally affects the performance of the rocket propelled vehicle.